The strange thing is, with/without cable plug in the tuner, the system report the same that WGAAGC/PLL was locked, which was showd below. Does anybody has this kind of experience? Thanks a lot! .... dvb_frontend_autotune: drift:0 inversion:0 auto_step:2440 auto_sub_step:0 started_au0 westlake_stv0297_pll_set: params->frequency is 0x208b4c80. Write data into PLL: 0x24 0x62 0xce 0x4. Call i2c_transfer return 0. data in PLL-data[0]: 0x7f. PLL locked. wait for WGAGC lock OK. wait for equaliser partial convergence OK. wait for equaliser full convergence OK. FEL status Locked wait for main lock timeout. Keep in FAST b/c dvb_frontend_autotune return 0. stv0297_read_status, sync = 0x0. fast zigzag. ....